Metal tube



(Ho Modem J. GARLSON.

METAL TUBE.

Patented Mar. 24, 1896.

Zia 62hr:

FIG. 1?.

all W2 ANDREW GRAHAM4MOIG'UTHQWASHINFWND Cv 'metal tube on line 1 1, Fig. 2.

UNITED STATES PATENT OFFICE.

JOHN CARLSON, OF BROOKLYN, NEW YORK, ASSIGNOR TO THE SEAMLESS STRUCTURAL TUBE COMPANY, OF JERSEY CITY, NEW JERSEY.

M ETAL TUBE.

SPECIFICATION forming part of Letters Patent No. 556,805, dated. March 24, 1896.

Application filed August 2, 1895. Serial No. 557,941. (No model.)

To all whom it nmy concern.-

Be it known that 1, JOHN GARLSON, of Brooklyn, New York, have invented an Improved Metal Tube, of which the following is a specification.

This invention relates to a metal tube to be used for bicycle-forks and for other purposes, and which is so constructed that great strength and at the same time great lightness is obtained. I

In the accompanying drawings, Figure 1 is a longitudinal central section of my improved Fig. 2 is a longitudinal section on line 2 2, Fig. 1. Fig. 3 is a cross-section on line 3 3, Figs. 1 and 2. Fig. 4 is a cross-section on line 4 4, Figs. 1 and 2. Fig. 5 is a cross-section on line 5 5, Figs. 1 and 2. Fig. 6 is a cross-section on line 6 6, Figs. 1 and 2. Fig. 7 is a cross-section on line 7 '7, Figs. 1 and 2.

The letter A represents my improved metal tube, which is slightly curved at its lower end, as shown. The tube gradually tapers from top to bottom, Figs. 1 and 2, and has an oval cross-section, Figs. 3 to 6. At the top the metal comprising the tube is thickened to form an inner abrupt integral reinforced section or shoulder a, that projects into the bore of the tube. At the bottom the metal comprising the tube is also thickened to form a similar abrupt integral reinforced section or shoulder a, that projects also into the bore of the tube. The tube is closed at its lower end by passing it through rolls and flattening it out, Figs. 2 and 7. It will be seen that by thickening the lower section of the tube the latter need not be pressed together to an undue extent while flattening it, and at the same time the necessity of introducing an additional core-piece is avoided. Thus the closing operation of the tube is facilitated and additional strength is obtained. If the tube is to be used for bicycleforks, the lower flattened end is perforated, as at a to constitute an axle-bearing.

Between the reinforced sections a. o. the wall of the tube A is reduced, as at a such reduced section extending from the lower end of section a to the upper end of section a, Fig. 1, and in this way the proper lightness for the body of the tube is obtained. If desired, the thickness of this reduced section a may gradually diminish, as indicated in Fig. 2.

The cross-section of the tube A is oval, as already stated. A cross-section through its reinforced end a shows the wall of the tube to be here throughout of even thickness, Fig. 3 but the cross -sections through the reduced body a? show the wall of the tube to be here of uneven thickness, Figs. 4 to 6that is to say, the tube is thickest at the ends of its minor axis and gradually diminishes toward the ends of its major axis, where the minimum thickness is obtained. The effect of this construction is that the tube is there strengthened by an increase in thickness, where its oval form would otherwise leave it weakest, and in this way the tube is well adapted to bear a transverse strain. Taken as a whole, therefore, the tube will ofi'er great resistance .to longitudinal and transverse strains, while at the same time the greatest possible lightness is always maintained.

What I claim is A metal tube substantially elliptical in cross-section, thinnest at the ends of the major axis of said section, and having its end compressed along said major axis or line of minimum thickness into a flattened portion, 80 substantially as described.

JOHN CARLSON.

WVitnesses WILLIAM ScHULz, F. v. BRIESEN. 

